AP BIOLOGY

Detailed explanation-1: -Silent mutations occur when the change of a single DNA nucleotide within a protein-coding portion of a gene does not affect the sequence of amino acids that make up the gene’s protein.

Detailed explanation-2: -A silent mutation (quiet mutation) is a form of mutation that does not cause a major change in the amino acid. As a result, the protein remains active and functional. Because of this, the changes are viewed as though they are neutral in terms of evolution.

Detailed explanation-3: -Silent mutations are mutations, or changes, to a gene’s DNA sequence that have no effect on the amino acid sequence coded for by that gene; they are called silent because their effect cannot be heard.

Detailed explanation-4: -Silent mutations lead to a change of one of the letters in the triplet code that represents a codon, but despite the single base change, the amino acid that is coded for remains unchanged or similar in biochemical properties. This is permitted by the degeneracy of the genetic code.

Detailed explanation-5: -One example of this is seen with a silent mutation of the adenomatous polyposis coli (APC) tumor suppressor gene at codon 623 from CGC to CGT (both cysteine encoding), which causes removal of exon 14 and creates a truncated protein.